Rare earth element-doped oxide precursor with silicon nanocrystals

Abstract

A method is provided for forming a rare earth element-doped silicon oxide (SiO2) precursor with nanocrystalline (nc) Si particles. In one aspect the method comprises: mixing Si particles into a first organic solvent, forming a first solution with a first boiling point; filtering the first solution to remove large Si particles; mixing a second organic solvent having a second boiling point, higher than the first boiling point, to the filtered first solution; and, fractionally distilling, forming a second solution of nc Si particles. The Si particles are formed by immersing a Si wafer into a third solution including hydrofluoric (HF) acid and alcohol, applying an electric bias, and forming a porous Si layer overlying the Si wafer. Then, the Si particles are mixed into the organic solvent by depositing the Si wafer into the first organic solvent, and ultrasonically removing the porous Si layer from the Si wafer.

Description

RELATED APPLICATIONS[0001]The application is a continuation-in-part of a application entitled RARE EARTH ELEMENT-DOPED SILICON / SILICON DIOXIDE LATTICE STRUCTURE, invented by Li et al, Ser. No. 11 / 039,463, filed on Jan. 19, 2005 and issued as U.S. Pat. No. 7,256,426, which is incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]This invention generally relates to integrated circuit (IC) fabrication and, more particularly, to a procedure for making a rare earth element-doped silicon oxide (SiO2) precursor with nanocrystalline (nc) Si particles, for use in silicon-based electroluminescence (EL) devices.[0004]2. Description of the Related Art[0005]The observation of visible luminescence at room temperature, emanating from porous silicon (Si), has spurred a tremendous amount of research into using nano-sized Si to develop a Si-based light source. One widely used method of fabricating nanocluster Si (nc-Si) is to precipitate the nc-Si out of SiO...

AI Technical Summary

Benefits of technology

The patent describes a new and economical way to make a layer of silicon oxide with nanocrystalline silicon particles and rare earth doping. This method allows for better control of the concentration of silicon in the layer, is cost-effective, and allows for direct attachment of rare earth elements to the silicon particles. The method involves mixing silicon particles into an organic solvent, filtering the solution to remove large particles, and mixing a second organic solvent with the filtered solution. The rare earth element particles are then mixed into the second solution, which is simultaneously mixed with a spin-on precursor solution for silicon oxide thin films. This results in a SiO2 precursor with nanocrystalline silicon and rare earth particles.

Problems solved by technology

However, state-of-the-art implantation processes have not been able to distribute the dopant uniformly, which lowers the light emitting efficiency and increases costs.

At the same time, there has been no interface engineering sufficient to support the use of such a dopant.

The device efficiency is very low and the process temperature is very high, which limits the device applications.

Silicon has conventionally been considered unsuitable for optoelectronic applications, due to the indirect nature of its energy band gap.

Bulk silicon is indeed a highly inefficient light emitter.

However as mentioned above, the device efficiency is very low and the process temperature is very high, normally over 1100° C.

That is, the making of a large area of Si—SiO2 interface is a critical issue for EL device applications.

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